I have only done this once and really liked the book i picked up. I was shooting with the Air Cadets and their is a LOT of waiting about for your go and on the table was 3 Para by Patrick Bishop. I had a little bit of debating about it because its not a genre i really read, but started to read it.
I enjoyed it that much i had to borrow a copy from my boyfriend, who luckiely already owned the book (how bizarre was that!)
I enjoyed this book so much its one of the genres i read now. So i think you should always give different genres a go, because you never know, you might like it.